A sample of HII galaxies has been observed in several radio and optical bands. These galaxies are undergoing very active star formation; they have been selected on the basis of strong radio continuum emission. Radio continuum observations were obtained to determine their radio spectra. Several of the spectra were found to flatten towards lower

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We present new results from the analysis of 55 high-resolution spectra of V404 Cyg (the optical counterpart of the X-ray transient GS 2023+338) taken in 1991 July-August which, added to our 1990 July Hα spectra, establish the most complete spectroscopic data base in quiescence of this new black hole candidate. In addition, we present multicolour

We have obtained the best fit to the light profiles of a luminosity- limited sample of elliptical and S0 galaxies with a power law r^1/n^, letting the exponent remain free rather than keeping it fixed at 1/n = 1/4 as in the well-known de Vaucouleurs formula. The introduction of a free parameter in the fitting formula (ranging from n = 0.5 for (r_e_

Models of the origin of spheroidal stellar systems, or cluster formation scenarios, need to account for empirical correlations both between scale and velocity dispersion σ and between luminosity and σ found in star-forming regions and relaxed spheroidal stellar systems. The model here proposed accounts for both correlations if the stellar system